1. Field of the Invention
The invention relates to a method of controlling an image reproduction system, wherein a process duration for processing a reproduction job is estimated on the basis of a measured time for the processing of a number of pages that have been processed already.
2. Background of the Invention
In an image reproduction system, e.g. a printing system, it is a typical scenario that a plurality of print jobs are waiting in a print queue until they are processed. An electronic controller of the printing system has, among other things, the task to schedule the print jobs, i.e. to establish a time table showing the timings at which the jobs will be processed and at which certain actions related to the processing of the print jobs will have to take place. The schedule is typically displayed on a user interface so as to give the users at least a rough estimate as to when their jobs will be processed and when they may be expected to be ready. More importantly, the schedule permits to alert an operator of the printing system of the timings at which certain actions, such as providing a supply of media sheets of a specified type, removing printed copies from a discharge tray, and the like are necessary in order to keep the system running.
In the course of the scheduling process, it is necessary to estimate process durations for the processing of the individual print jobs and/or for processing certain collections or sets of pages to be printing within each print job. Such estimates may be based on a model of the print job, wherein the print job is segmented into a number of actions to be taken and an expected duration is specified for each individual action, so that it is possible to calculate an estimate for the total duration that will be needed for printing and possibly finishing a certain number of pages or for completing an entire print job, while taking into account that certain actions that may be performed in parallel.
However, the estimated durations for the individual actions are known only with a limited accuracy and may also vary in the course of time, due to changes in the processing conditions, such as environmental temperature, and the like. Additionally, combinations of actions may also lead to variations in time. Consequently, the estimates obtained on the basis of the model will inevitably involve a certain error.
It is known to improve the accuracy in the prediction of a process duration for a print job by correcting the estimated process duration in a feedback loop in which, when a certain number of pages have been completed, the processing time that has actually been needed is compared to the model-based time estimate, and the estimate for the next few pages to be printed is corrected accordingly. Consequently, the time when a print job will be ready can be predicted with higher accuracy.
EP 3001304 proposes a method in which an estimate for the duration of a print job is corrected by multiplying it with a correction factor that may be edited by the user.